Citing new estimates set to be released in November, the director of the National Center for AIDS/STD Control and Prevention said HIV continues to spread in China, chiefly by sexual transmission from persons in high-risk groups.

"The rise of the HIV/AIDS epidemic has yet to be under effective control," said Wu Zunyou. "In the past five years, the number of new cases surpassed 40,000 every year."

China's cumulative total of known HIV/AIDS cases, including persons who have died, was 264,300 in September 2008 and had climbed to 295,000 by May 2009. UNAIDS, however, believes a more accurate count would exceed 700,000 cases. Unprotected sex is the transmission route for 57 percent of new cases, according to UNAIDS.

"HIV transmission through unsafe sex is particularly dangerous to the general public because it's now the leading cause of HIV/AIDS transmission in China, instead of needle sharing among drug users," Wu said.

Although monitoring and testing services have been expanded, Wu said communicating with gay men and sex workers, two hard-hit groups, is challenging. Health education is reaching only an estimated 14.2 percent of gay men and 43.3 percent of prostitutes. "We need to encourage more people from these groups to stand up and help raise AIDS awareness among their peers," Wu said.

Another growing trend is more infections among older people, Wu noted. The number of men age 60 and over who became infected was 483 in 2005 but reached 1,713 in 2008. "Once infected, they are more likely and quickly to develop into AIDS patients because their immune systems are weaker than young people," Wu said.